Reaves has written for a number of animated television shows, including Transformers, Teenage Mutant Ninja Turtles and Batman. He also co-wrote the 1993 animated film Batman: Mask of the Phantasm. He more recently wrote several episodes of Spider-Man Unlimited.

His live-action writing credits include an episode of the 1980s version of The Twilight Zone starring Richard Cox, an episode of Father Dowling Mysteries guest-starring Michelle Forbes and Natalia Nogulich, and the Sliders episode "Requiem", directed by Paul Lynch.